Process for obtaining pipes and joints from a polymer composite

ABSTRACT

A “PROCESS FOR OBTAINING PIPES AND JOINTS FROM A POLYMER COMPOSITE” comprising an inner pipe ( 1 ), 3.0 to 8.0 mm thick, made of fiber glass with an epoxy resin matrix for resisting the corrosion of the produced fluids and the abrasion of the solid suspended particles. They are made in a metal polished mold through the “filament winding” process with roving thread at a winding angle of 52° to 55°, impregnated with epoxy resin and catalyzed with an aromatic amine, anhydride and aliphatic amine-based cold cure agent, in order to stand chemical attacks and temperature, with the ends being made from molds with a molded thread made of an epoxy resin and carbon fiber compound, wherein the outer face suffers a sanding down process which decreases brightness and adherence in order to accommodate a second layer of “filament winding”, with roving thread at a winding angle between 80° and 85°, 5.0 mm and 8.0 mm thick, impregnated with cold cured cobalt accelerated polyester resin, with an added silica-based charge, with a weight of 40/60 which is deposited through gravity spillage intertwined between the filament winding layers, structured so as to mechanically assist in case of impacts, providing assistance to the product&#39;s structural protection, increasing mechanical resistance, essentially as regards impacts and loads on wheels, so that over the second layer a 1.0 to 4.0 mm thick cold cured third polyurethane layer is deposited, the aim of which is providing the pipe with a metal structure, increasing its resistance to impacts and the elements.

This application for a patent of invention refers to a “PROCESS FOR OBTAINING PIPES AND JOINTS FROM A POLYMER COMPOSITE”, developed with the aim of providing non metal pipes and joints, manufactured from a polymer composite material for application in flow lines in oil wells, water injection, fresh water injection, salt water injection, treated water injection and CO2 injection, in oil fields, the structural features of which allow it to bear mechanic impacts, loads on wheels, exposure to the elements, a maximum fluid temperature of 95° C., operative pressure of 500 to 3000 PSI, chemical corrosion and abrasion wearing out caused by the suspended silica in the fluid (water, oil and gas from the oil well). This technological innovation replaces flow lines in wells which are currently made of API 5L GR B material.

STATE OF THE ART

Currently oil companies use elevated flow lines made of 3-inch diameter API 5L GR B steel, maximum pressure 1000 psi and maximum operation temperature of 65° C., for the production of crude oil (oil, gas and water). Said lines are used in large scale and thousands of kilometers have been installed to this date. Said production facilities are subject to atmospheric corrosion and electrical-chemical corrosion according to the environment in the oil wells and the fluids produced thereby. Many of these wells are deemed as critical due to the fluid they produce which causes early wearing away and internal corrosion of the metal flow lines. As a means of exemplifying said scenario, we mention that some of these lines which depend on the composition of the produced fluid suffer leaks after less than one year of operation due to internal corrosion.

The pipes used in flow lines, especially steel ones, are subject to wear and tear, not only due to mechanical action (wear and tear) but to chemical or electrical-chemical action (corrosion), or the joint action of both.

During internal corrosion, the oxygen existing in the water vapor contained in the atmospheric air largely accounts for oxidation and occurs everywhere, even inside the pipe. Therefore, this promotes oxidation mainly in the shape of pits (gaps with angular bottoms and whose depth is mostly larger than their diameter) which decrease the tube's useful life. This type of corrosion accounts for about 20% of the total corrosion which occurs inside the pipe.

The internal corrosion of metals close to the littoral is a process which is due to the presence of salts dissolved in the water droplets, which turns the solution electrolytic. With the increase of the flow of electric charges (ions) in the solution the corrosion process is favored due to the oxidizing power of the oxygen in atmospheric air. In the case of the pipe, external corrosion appears uniformly, and is the main cause of pipe mass loss (nearly 80%), since it appears throughout the surface extension and causes a uniform thickness loss on the exposed layer.

Due to the problems caused by metal pipes, epoxy resin-based fiber glass pipes began to be used, which have been successfully employed in highly aggressive environments where steel and its alloys last only weeks or months. The exceptional corrosion resistance of the compound based in said materials in contact with alkaline and acid environments, and even solvents has been confirmed and well documented for decades. The exceptional chemical resistance of these pipes allows their application in most cases where conventional materials are destroyed by corrosion. They afford cathodic protection due to their extremely low electric conductivity.

The compound made of epoxy resin-based fiber glass affords lightness, good mechanical properties and exceptional chemical inertia in a wide range of aggressive environments.

But fiber glass pipes may only be used below the ground, and there is also a need to dig trenches with an average depth of 60 cm and 40 cm of width, checking the same first for any stones or hard particles which may make contact with the pipes and damage them, due to which the trenches must have a layer of sand on the bottom where the pipes are deposited, and then they must be covered with another layer of sand, and only then may the earth dug out from the trench be replaced (backfill).

When a length of pipe must be placed in the air in order to cross brooks or other obstacles, the pipes are encased. This procedure is used both as a way of protecting the pipe against solar rays and as a protection against vandalism. Said encasing is then painted and inscriptions regarding the material transported, pressure, etc. are printed on it. The encasing covers the whole elevated portion and enters the ground at least 50 cm. In order to avoid contact with the encasing the pipes are protected with rubber strips.

In spite of their good applicability regarding corrosion, these pipes have low resistance to impacts, and may only be used underground, in deep trenches, which increases project costs, and thus impacts caused by wheels are also avoided.

Due to their low resistance to impacts, fiber pipes are not used in elevated flow lines, thus forcing oil companies to use metal pipes which need constant maintenance and cause stops in the lines, causing financial damages.

Technological advances in the field of composites applied to the oil industry are increasing all the time, and in answer to this scenario and with the aim of solving all technical issues wherein metallic materials do not respond successfully to the process due to their limitations, this invention proposes a “PROCESS FOR OBTAINING PIPES AND JOINTS FROM A POLYMER COMPOSITE”, which comprises an inner pipe (1), with a thickness of 3.0 to 8.0 mm, made of fiber glass and an epoxy resin matrix for resisting fluid corrosion caused by the abrasion of the solid suspended particles. It is made of a metal polished mold, through a filament winding process, with roving thread at a 52° to 55° winding angle, impregnated with epoxy resin and catalyzed with an amine, anhydride and aliphatic amine-based hot curing agent, for bearing chemical attacks and temperature, with the ends made from molded thread molds with an epoxy resin and carbon fiber-based compound, so that the outer face (2) of the inner layer (1), suffers from a sanding down process which decreases brightness and adherence so that a second layer (3) of “filament winding” with roving thread, may be placed, at a winding angle of between 80° and 85°, 5.0 mm to 8.0 mm thickness, impregnated in cold cured cobalt accelerated polyester resin, with an added silica-based charge, with a weight of 40/60, which is deposited through gravity spillage, inserted between the “filament winding” layers, structured so as to provide mechanic assistance in case of impacts, thus increasing the product's structural protection and increasing mechanical resistance, essentially as regards impact and loads on wheels, in such a way that over the second layer (3) a third cold cured polyurethane layer (4) is laid with a thickness varying between 1.0 and 4.0 mm, whose aim is to provide the pipe with a mechanical structure, increasing its resistance to impacts and to the elements.

In order to achieve comprehensive understanding of what has been disclosed, illustrative figures are included with number references together with the detailed description, wherein:

FIG. 1 shows a side view of the fiber pipe.

FIG. 2 shows a longitudinal section of the pipe with reference to the three layers.

FIG. 3 shows a cross-section of the pipe with reference to the three layers.

Based on the foregoing disclosure we may appreciate that the “PROCESS FOR OBTAINING PIPES AND JOINTS FROM A POLYMER COMPOSITE”, provides enormous benefits, since the pipe is made of a polymer composite for application in oil wells flow lines, fresh water injection, salt water injection, treated water injection and CO2 injection in oil fields, which successfully resist mechanical impacts, loads on wheels, corrosion, a maximum temperature of 95° C., a pressure of 500 to 3000 PSI, and the elements.

The process herein claimed presents a pipe which internally is highly resistant to the corrosion caused by the soil (clay with high silica contents) and by the produced fluids (water, oil and gas), as well as highly resistant to the abrasion caused by the solid particles (silica from the well) suspended in such fluid. And externally, affords high mechanical resistance to impacts and loads on wheels, as well as to the elements.

It is also relevant pointing out that the pipe made with 3 layers has the following benefits:

-   -   It is more easily assembled. It does not require welding or         highly skilled labor;     -   Personnel and equipment may freely move over the installed areas         when they are underground;     -   When the lines are buried they need no anchorage;     -   Mechanic equipment is not necessary for handling and setup         thereof since the pipes are lighter;     -   A larger number of tubes may be installed per man hour;     -   They reduce visual environmental impact.     -   Lower costs in comparison to elevated Steel Flow Lines;     -   Longer useful flow line life;     -   High resistance to the elements, including ultraviolet rays;     -   Needs no external paint;     -   Extremely high resistance to internal and external corrosion         from the following fluids:

Internal

-   -   Oil     -   Fresh Water     -   Produced Water     -   Salt Water     -   CO₂     -   H₂S

External:

-   -   Oil     -   Fresh Water     -   Produced Water     -   Salt Water     -   CO₂     -   H₂S     -   Acetone     -   Methyl ethyl ketone

This technological innovation is a technical proposal for replacing metal flow lines in oil wells which are currently made of API 5L GR B material, and thus, since it is novel and not comprised within the state of the art may fit perfectly within the definition of an invention. The following is claimed. 

1. A “PROCESS FOR OBTAINING PIPES AND JOINTS FROM A POLYMER COMPOSITE”, comprising an inner pipe (1), with a thickness of 3.0 to 8.0 mm made of fiber glass and epoxy resin matrix, made in a polished metal mold through the process known as “filament winding”, with roving thread at a winding angle of 52° to 55°, impregnated in epoxy resin and catalyzed with an aromatic amine, anhydride and aliphatic amine-based hot curing agent, with its ends made from thread molds molded with an epoxy resin and carbon-based compound, wherein the outer face (2) of the inner pipe (1) undergoes a sanding down process, thus creating a porous surface.
 2. The “PROCESS FOR OBTAINING PIPES AND JOINTS FROM A POLYMER COMPOSITE”, as set forth in claim 1, wherein the outer face (2) of the inner pipe (1) receives a second layer (3) of “filament winding”, with roving thread at a winding angle between 80° and 85°, 5.0 mm to 8.0 mm thick, impregnated with cobalt accelerated polyester resin which is cold catalyzed with a cold polyester catalyzer, with an added silica charge and a 40/60 weight.
 3. The “PROCESS FOR OBTAINING PIPES AND JOINTS FROM A POLYMER COMPOSITE”, as set forth in claim 1, wherein the cobalt accelerated polyester resin which is cold catalyzed with a cold polyester catalyzer, with an added silica charge and a 40/60 weight, is deposited between the filament winding layers.
 4. The “PROCESS FOR OBTAINING PIPES AND JOINTS FROM A POLYMER COMPOSITE”, as set forth in claim 1, wherein over the second layer (3) a third layer of cold cured polyurethane (4) is deposited with a thickness from 1.0 to 4.0 mm.
 5. The “PROCESS FOR OBTAINING PIPES AND JOINTS FROM A POLYMER COMPOSITE”, as set forth in claim 1, wherein the final composition of the pipe has a mechanic structure which resists impacts and the elements.
 6. The “PROCESS FOR OBTAINING PIPES AND JOINTS FROM A POLYMER COMPOSITE”, as set forth in claim 1, wherein the resistance to impacts is determined by the thickness of layers (3) and (4).
 7. The “PROCESS FOR OBTAINING PIPES AND JOINTS FROM A POLYMER COMPOSITE”, as set forth in claim 1, wherein the composition of the pipe allows for its use in elevated flow lines. 